Abstract Although more than one decade has passed since the WTC attack, its lasting effect on the mental health of thousands of individuals remains constant. Although major efforts were made in the identification and treatment of mental health problems among adults who were exposed to the WTC attack, other than school programs much less was done for those children who exposed to this massive traumatic. Given the fact that exposure to trauma early in life potentially has a significant long-term impact on a persons life, the need to better understand the service needs of this population is critical. In response to the program announcement from the National Institute for Occupational Safety and Health (NIOSH), entitled oeCooperative Research Agreements Related to the World Trade Center Health Program (U01)? the proposed study will examine mental health service need and use among youth who were exposed to the WTC attack during their childhood. Two groups of youth, those who were directly exposed to the WTC attack during their childhood and those whose parents were directly exposed to the WTC attack, will be examined. The study will include data from two unique samples: 1) 1,244 youth who were exposed to the WTC attack during their childhood and participated World Trade Center Health Registry (WTCHR) survey, and 2) 883 youth whose parents were exposed to the WTC attack and who, therefore, were indirectly exposed to the WTC attack through their parents. The proposed project will assess mental health service need, use and barriers to access to mental health services by identifying factors associated with youth mental health service utilization, including predisposing and enabling factors at the individual, family, school and community levels, and examine the impacts of parental exposure to the WTC attack, parental psychopathology and parental help seeking behaviors on childrens patterns of mental health service utilization; and develop and test a model of adolescent mental health service utilization after the WTC attack. It is hoped that the findings from this project will provide valuable information to clinicians and policy makers for improving the delivery of mental health treatment to those in need, both for this 9/11 population and those exposed to other, subsequent disasters.